The genus name is from Ancient Greek onux, "claw" or "nail", and prion, "saw".

[5] Within the genus, Aleutian tern is the most divergent, splitting off from the rest about ten million years ago; then sooty tern diverged about seven to eight million years ago, and finally bridled and spectacled terns diverged from each other about three million years ago.

The Aleutian tern breeds around Alaska and Siberia but winters in the tropics around South East Asia.

Manutara is the Rapa Nui language name for spectacled and sooty terns.

Both arrive at Easter Island and hatch their eggs on the island called Motu Nui, an event that was used for an annual rite called Tangata manu.